Segment Information (Schedule Of Geographic Information On Sales To External Customers, Based On Country Of Origin) (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended								12 Months Ended
	Dec. 31, 2011	Sep. 30, 2011	Jun. 30, 2011	Mar. 31, 2011	Dec. 31, 2010	Sep. 30, 2010	Jun. 30, 2010	Mar. 31, 2010	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Revenues from External Customers and Long-Lived Assets [Line Items]
Net sales	$ 303,754	$ 298,241	$ 294,733	$ 276,499	$ 285,005	$ 242,019	$ 237,173	$ 212,434	$ 1,173,227	$ 976,631	$ 909,991
United States [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenue from External Customers									538,257	447,029	422,349
Germany [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenue from External Customers									75,536	77,858	79,553
Other [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenue from External Customers									$ 559,434	$ 451,744	$ 408,089